1. Field
The present disclosure relates to a fan.
2. Background
Generally, in an air conditioner, indoor or outdoor air is blown by a fan, and the blown air exchanges heat with refrigerant flowing in an evaporator or coolant flowing in a heater. Air cooled or heated through such heat exchange is blown into an indoor area for cooling or heating the indoor area.
FIG. 1 is a perspective view illustrating a fan 1 of the related art.
Referring to FIG. 1, the fan 1 of the related art includes: a hub 10 that may be connected to a motor; and a plurality of blades 20 extending from the hub 10. The blades 20 have positive-pressure surfaces 24 and negative-pressure surfaces 25 opposite to the positive-pressure surfaces 24.
Air stream on the blades 20 will now be explained.
Referring to FIG. 1, if the blades 20 are rotated counterclockwise, air flows on rear surfaces of the blades 20 and is separated therefrom. Due to the separation of air, noise is generated.
Recently, large-capacity air conditioning systems are widely used, and such large-capacity air conditioning systems require high air flow rates. If the air flow rate of an air conditioning system is high, more noise is generated when air flows through a fan. Such noise of a fan annoys users.
Embodiments provide a fan in which less air-stream noise is generated from blades.
In one embodiment, a fan comprises a hub and a blade extending from the hub. The blade comprises a blade rear end having a predetermined curvature and a blade side end connected to the blade rear end. The blade rear end comprises an alternating pattern of ridge parts and groove parts, the pattern extending along the edge of the blade rear end. For example, the alternating pattern of ridge parts and groove parts provides an overall wave shape or meandering shape of the blade rear end.
The ridge parts and the groove parts may extend from the blade in opposite directions in the area of the blade rear end.
For example, the ridge parts protrude in a predetermined direction from an extension and the groove parts protrude in a direction opposite to the predetermined direction. Herein, the extension may be an imaginary line connected from a first point at which the hub and the blade rear end meet to a second point at which the blade side end and the blade rear end meet.
The ridge parts and the groove parts may be rounded with predetermined curvatures.
The ridge parts and the groove parts may be alternately arranged so that sounds generating from air flowing on the ridge parts and the groove parts cancel out each other.
A distance between adjacent two of the ridge parts is preferably equal to a distance between adjacent two of the groove parts.
The alternating pattern may comprise a first connection part extending from a first upper end part of the pattern to a first lower end part of the pattern being next to the first upper end part, and a second connection part extending from a second upper end part of the pattern being next to the first upper end part to the first lower end part of the pattern.
The first connection part may be in contact with the second connection part.
The first upper end part and the second upper end part may be pointed end parts.
The first lower end part may have a width D between the first connection part and the second connection part. The first upper end part may have a width C being equal to the width D of the first lower end part.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.